单轴旋转INS/GPS组合导航中重力垂线偏差引起的姿态误差分析

Analysis of gravity vertical deflection-induced attitude error in single-axis rotation INS/GPS integrated navigation system

重力垂线偏差是高精度惯性导航中的一个主要误差源。在INS/GPS组合导航系统中,由于GPS可以提供位置和速度修正信息,垂线偏差对组合导航系统精度的影响主要体现在姿态上。从惯性导航系统的误差方程出发,推导INS/GPS组合导航姿态估计误差和陀螺零偏估计误差的解析表达式,从理论上分析组合导航模式下垂线偏差对姿态误差的影响。通过仿真验证理论分析的正确性。分析结果表明:东向姿态误差角由北向垂线偏差决定,北向姿态误差由东向垂线偏差决定;航向误差受东向垂线偏差和北向垂线偏差的一阶导数的共同影响,垂线偏差的剧烈变化将引起较大的航向误差。

Gravity deflection of the vertical(DOV) is one of the main error sources in high-precision inertial navigation. As the gravity-induced position error can be easily dumped in GPS/INS integrated navigation, the attitude estimation errors are more affected by DOV. In this paper, theoretical analysis of the gravity-induced GPS/INS navigation attitude errors is presented. The analytical results of attitude errors due to DOV are derived based on the inertial navigation error model, and the gyro bias estimation errors are analyzed accordingly. The numerical simulation results agree well with the theoretic analysis. The analysis results show that the east and north attitude errors are affected by north and east DOV respectively, while the yaw error is affected by east DOV and the first derivative of north DOV, meaning that the abrupt change of DOV may result in significant yaw error.